docs: def list(self, pattern='*'):
      """Returns a list of metric descriptors that match the filters.
  
      Args:
        pattern: An optional pattern to further filter the descriptors. This can
            include Unix shell-style wildcards. E.g. ``"compute*"``,
            ``"*cpu/load_??m"``.
  
      Returns:
        A list of MetricDescriptor objects that match the filters.
      """
      if self._descriptors is None:
        self._descriptors = self._client.list_metric_descriptors(
            filter_string=self._filter_string, type_prefix=self._type_prefix)
      return [metric for metric in self._descriptors
              if fnmatch.fnmatch(metric.type, pattern)]